I find that sort of thing odd for me as well, when a therapist is angry at someone on my behalf. Something about the degree of agency involved -- because of all the many people I have known in my life, from all walks of life, even those people who are closest to me don't ever do that. I mean, there was probably a boyfriend way back in high school who had that type of attitude, but it would have been one of the qualities that made me shy away from him. My friends are more than likely to offer support, or to help me think certain things through, like saying "what are you thinking of doing about X", but angry on my behalf? Not so much.

On the other hand, it must work for some people, that so many therapists express that sort of thing. I would agree it sounds canned, in my experience anyway.

I think they may be trying to encourage mirroring, something like showing what angry looks like if they think you're not accessing enough. Whether that's effective I couldn't say.